This invention involves several discoveries reached by experience, experimentation, and supportive analysis to improve significantly on the string network of tennis rackets, racquetball rackets, and other sport rackets. The effort generally is directed toward determining optimum string parameters and arrangements to make a string network that is more effective, efficient, and responsive in applying hitting force to a ball.
The invention not only recognizes that longer strings have important advantages, but it recognizes why longer strings work better and how they can be arranged to produce improved results. It includes several suggestions for extending longitudinal strings into the throat or shank region of a racket to have a substantially longer strung length; and it proposes several different arrangements for fanning out, guiding, and anchoring longer longitudinal strings.
The invention also recognizes that longer longitudinal strings should be strung with a higher tension than shorter transverse strings, and the invention determines both the reasons for and the extent of the higher tension for the longer strings to achieve a significantly better working relationship within the string network.
Investigation of the dynamics of string mechanics by using experimentation, mathematical analysis, and play experience has produced considerable verified information on truly effective lengths and tensions for the longitudinal and transverse strings to work effectively together. The information reveals that the necessarily shorter but equally tensioned transverse strings in prior art rackets bear much more than half of the load in hitting a ball. This not only wastes the superior capacity of the longitudinal strings to bear the ball-hitting load, but also contributes to twisting torque and shock delivered to the player's arm from shots hit off center.
The invention not only recognizes the advantages of longer longitudinal strings strung at higher tension than the shorter transverse strings, but also quantifies an approximate functioning relationship that balances the greater tension and length of the longitudinal strings with the lesser tension and length of the transverse strings effectively to apportion more of the ball-hitting load to the longitudinal strings. This gives a string network a higher coefficient of restitution imparting a higher velocity to a rebounding ball, spreads the higher coefficient of restitution throughout a wider network area, reduces losses from stretching and rubbing strings and deforming the ball, and lessens torque shock to the arm of the player. Tennis rackets strung according to the invention have been made, tested, and used in play to verify measureable data, confirm analysis, and establish subjectively that the invention produces better control, higher velocity returns, and a lively and shock-free feel in shot making.